The present invention relates to a liquid delivery apparatus, such as a liquid delivery apparatus that is to be used for distributing liquid waste, such as agricultural slurry, over agricultural land.
In U.S. Pat. No. 7,048,145, there is disclosed a liquid delivery apparatus comprising (i) a vessel into which a liquid may be introduced via an inlet to partially fill the vessel and to pressurize the liquid that partially fills the vessel and the air that fills the remainder of the vessel; (ii) an outlet via which said liquid may be discharged from the vessel under the pressure of the liquid and air in the vessel; (iii) a valve between the vessel and the outlet to control passage of liquid from the vessel to the outlet, said valve having (a) an opening, (b) a closure member adapted to close the opening, and (c) a biasing means, the arrangement of the components of the valve being such that the valve is normally held closed by the biasing means; (iv) a valve control mechanism for controlling the operation of the valve in response to the pressure of the liquid and air in the vessel; and (v) a means for transmitting the pressure of the liquid and air in the vessel to the valve control mechanism; wherein the valve control mechanism comprises a moveable element which is capable of being acted on by the pressure of the liquid and air in the vessel and transmitting a resultant force to the closure member of the valve in a direction to open the valve, and wherein the respective effective surface areas of the moveable element and the closure member and the force of the biasing means are chosen such that the closure member is openable when the pressure of the liquid and air in the vessel reaches a predetermined level.
The liquid delivery apparatus disclosed in the aforesaid patents suffers from undesirable pressure losses in the piping between the vessel and the outlet. These pressure losses result in a reduced reach of the spray and, since the coverage area depends on the square of the spray radius, the coverage is significantly reduced. The present invention seeks to address this and other issues.